From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752831AbaJPUTi (ORCPT ); Thu, 16 Oct 2014 16:19:38 -0400 Received: from mx1.redhat.com ([209.132.183.28]:10666 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752620AbaJPUTh (ORCPT ); Thu, 16 Oct 2014 16:19:37 -0400 Date: Thu, 16 Oct 2014 22:16:20 +0200 From: Oleg Nesterov To: Martin Schwidefsky Cc: linux-kernel@vger.kernel.org, Linus Torvalds , Andrew Morton , Tetsuo Handa Subject: Re: [PATCH] kernel/kmod: fix use-after-free of the sub_info structure Message-ID: <20141016201620.GA25225@redhat.com> References: <20141016160042.7f898871@mschwide> <20141016173733.GA18318@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20141016173733.GA18318@redhat.com> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/16, Oleg Nesterov wrote: > > OK... I am wondering if __call_usermodehelper() still needs CLONE_VFORK > with this patch. Yes, looks like it doesn't, but this needs another patch. > > @@ -588,7 +580,7 @@ int call_usermodehelper_exec(struct subprocess_info *sub_info, int wait) > > goto out; > > } > > > > - sub_info->complete = &done; > > + sub_info->complete = (wait == UMH_NO_WAIT) ? NULL : &done; > > This probably needs a comment, and the comment in umh_complete() should > be updated, > > - we own sub_info, the UMH_KILLABLE caller has gone away. > + we own sub_info, the UMH_KILLABLE caller has gone away > + or the caller used UMH_NO_WAIT. > > The patch looks correct at first glance. I'll try to re-read it later > once again. Reviewed-by: Oleg Nesterov